The Methods and Analysis Core has two main functions. First, to supply, operate and maintain the specialized equipment used in individual Research projects for monitoring a variety of overt circadian rhythms in rodents and humans, and to implement standard procedures for their computer storage. The Core also explores and validates novel techniques for non-invasive monitoring of overt circadian rhythms in humans and rodents. A second main function is to provide investigators in all five Projects with standard methods for reporting and analyzing temporal profiles of activity, temperature, sleep stages, hormonal levels, and behavioral variables. The Core also explores and validates novel methods for data analysis that are specially suited to the data obtained in the five Projects. The availability of a centralized pool of monitoring equipment prevents equipment duplication and provides the individual investigators with expert assistance for optimal operation and trouble-shooting of the equipment. The availability of standardized procedures for data reporting and analysis enables each investigator to extract as much information as possible from the collected data, and facilitates the integration of individual projects as well as communication between investigators. Standardization of data processing and analysis enables additional comparisons of various study groups across Projects, and thus more information can be derived from the Program Project as a whole than from the sum of each of its components. This core has also enabled the various projects to incorporate a variety of new approaches for recording and analyzing sleep and circadian rhythms. Of particular significance is the development of new approaches over the past 18 months for; 1) the quantitative analysis of circadian pattern fragmentation, 2) the use of a nw device for monitoring alertness under ambulatory conditions, 3) monitoring a range of cognitive functions, and 4) the recording of EEG and EMG waveforms in the hamster using a state-of- [unreadable]he-art system. The use of these and other new approaches developed by t his core will greatly enhance the overall quality and quantity of the data collected in the five projects.